GA Perception and Signal Transduction: Molecular Interactions of the GA Receptor GID1 with GA and the DELLA Protein SLR1 in Rice

摘要

Gibberellins (GAs) are diterpenoid plant hormones that promote a number of plant growth responses, including seed germination, stem elongation, leaf expansion, and flowering. GAs act by inducing the degradation of DELLA domain proteins that function as repressors of GA-dependent processes. Research over the past few years has uncovered the principal steps associated with GA perception and signal transduction in rice and Arabidopsis. Two years ago, Ueguchi-Tanaka et al. (2005) identified a GA receptor in rice, GIBBERELLIN INSENSITIVE DWARF1 (GID1), which encodes a soluble protein with similarity to hormone-sensitive lipases. Nakajima et al. (2006) cloned three homologous genes in Arabidopsis, called GID1a, GID1b, and GID1c, and confirmed that all three genes encode proteins that bind GA in vitro and rescue the GA-insensitive dwarf phenotype when expressed (individually) in the rice gid1 mutant.